efectuează scăderile repetate

Răspuns:
a)
4-2-2=0
12-3-3-3-3=0
24-6-6-6-6=0
20-5-5-5-5=0
b)
21-7-7-7=0
14-7-7=0
36-9-9-9-9=0
40-8-8-8-8-8=0